The purpose of this task order is to measure cytokines in placental samples frozen under two different protocols. This study will serve as a feasibility project for placenta specimens from the EAGeR trial, which will be the first trial to evaluate the effects of preconception LDA on cytokine levels in human placental tissue. The Effects of Aspirin in Gestation and Reproduction (EAGeR) trial was a multi-site, doubleblind, block-randomized, placebo-controlled trial designed to assess the effects of low-dose aspirin (LOA, 81 mg per day) in combination with folic acid (400 meg per day) on fertility and pregnancy outcomes among 1228 women with a history of pregnancy loss.' Use of LOA at the time of conception may lead to improved placentation, possibly through improved transformation of the uterine spiral arteries.2 3 Interestingly, among clinically recognized pregnancies in EAGeR, the risk of preterm birth was marginally lower in the LDA vs.placebo treatment arm (5.9% vs. 9.0%, P = 0.12) (Schisterman, in press). Placental tissue is available for 79% (473/595) of the study pregnancies resulting in live birth. Thus, we are interested in investigating sub-clinical differences in placental function between treatment arms, particularly given that LOA may have contributed to a slightly lower, yet not statistically significant, risk of preterm birth. Specifically, intracellular molecules involved in placental vascularity, including those involved in inflammation, angiogenesis and hypoxia are to be explored to understand the mechanistic effects of LDA with clinical outcomes such as preterm birth, preeclampsia and intrauterine growth restriction. However, before pursuing these investigations a foundation of knowledge for the optimal handling and processing of the existing EAGeR placenta samples is needed. In addition to the establishment of labor and cost estimates for processing these samples, we would like to determine whether cytokines (or which cytokines) have sufficient stability to remain unchanged by a 24 hour storage period at refrigerator temperature prior to freezing, as was allowed in the EAGeR trial specimen collection protocol. This information will help us develop specific proposals in the future aimed at examining LOA's effect on placental cytokine levels using the stored EAGeR samples.